127 - Microbiología Ambiental, Agrícola y del Suelo

ANTIFUNGAL EFFECT OF METABOLITES EXTRACTED FROM FUNGAL STRAINS ON ENTOMOPATHOGENIC STRAINS OF Apis mellifera.

Tejerina, Marcos R.^{1 2 3}- Ruiz Gisela B.^{1 2 3}- Salas Zapana Micaela¹-Chavarria Daiana D.¹-Mamani, Soledad E.¹-Tapia Fernando E.¹-Vilte, Yanina M.¹-Benitez Ahrendts Marcelo R. ^{2 3}-Fonseca María I.^{4 5}

1) Catedra de Microbiología Ambiental, Facultad de Ciencias Agrarias-UNJu- San Salvador de Jujuy-Jujuy-Argentina.
2) Laboratorio de Sanidad Apícola y Meliponicola- Facultad de Ciencias Agrarias- UNJu- San Salvador de Jujuy-Jujuy-Argentina.
3) Instituto de Ecorregiones Andinas, Consejo Nacional de Investigaciones Científicas y Técnicas (INECOA-CONICET)- San Salvador de Jujuy-Jujuy-Argentina.
4) Universidad Nacional de Misiones, Facultad de Ciencias Exactas, Químicas y Naturales. Instituto de Biotecnología “Dra. María Ebe Reca” (INBIOMIS), Laboratorio de Biotecnología Molecular. Misiones, Argentina
5) CONICET, Buenos Aires, Argentina
Contacto: tejerina.marcos@yahoo.com

Ascosphaera apis and Aspergillus flavus are entomopathogens that affect the development of A. mellifera bee larvae, which causes a decrease in the individuals in the colonies. In recent years, it has been reported that bees interact with various species of fungi for beneficial purposes such as food and medicine. Four fungal strains Trametes hirsuta, Skeletocutis spp., Trichoderma spp. and Pleurotus ostreatus. All isolated fungal strains were grown on 50g of sterile brown rice for 10 days at 28°C under static conditions, the inoculum was subsequently macerated and suspended in 60 mL of ethanol (70%), to a final concentration of 0.8 g/mL. The preparation was filtered and the metabolic solution was concentrated by distillation at 70°C. 10 mL of metabolic concentrate (MC) was extracted from each fungal suspension and stored at 5°C until use. For the inhibition assays, 1 mL of each extract was resuspended in 25 mL of My20 liquid medium and malt extract to test the growth effect of A. apis and A. flavus respectively. Cultures were incubated on a shaker at 30°C for 10 days for A. apis, while media for A. flavus were incubated on a shaker at 25°C for 5 days. After this period, the grown mycelia were weighed and the biomass was determined. All tests were performed in duplicate. Only the entomopathogenic strains grown in both media without metabolic suspensions were used as a control. Mycelial weights were expressed as mean±standard deviation. Statistical analysis was performed using ANOVA and Turkey's mean comparison test with a 0.05 probability of committing a type I error. All MC showed significant differences in the growth effect of entomopathogenic strains, for A. apis it was p<0.001 and for A. flavus it was p<0.0047 concerning the controls. The weights of the biomass grown with MC of Trametes hirsuta were 1.74±0.06g for A. apis and 0.95±0.37g for A. flavus; with MC of Skeletocutis spp. was 1.46±0.17g for A. apis and no growth for A. flavus; with MC of Trichoderma spp. not recording mycelial growth for A. flavus was 0.82±0.88g and the MC of Pleurotus ostreatus there was no mycelial growth for A. apis, and 0.77±0.24g for A. flavus. The controls recorded weights of 3.23±0.32g for A. apis, and 4.8±1.13g for A. flavus. The MC of the fungal strains has an antifungal effect on both entomopathogens, which is why they could be potential biological controllers of these diseases.

Palabras clave: Biocontrol-Bee-Metabolites